Water Treatment Operator-in-Training (OIT) Practice Test

A substance must produce an insoluble floc to effectively act as a coagulant in water treatment. Coagulation is a crucial process used to remove suspended particles, turbidity, and colloidal substances from water. When a coagulant is added to water, it destabilizes the particles, allowing them to clump together and form larger aggregates known as floc.

The formation of an insoluble floc is essential because it allows for easier removal from the water during subsequent treatment processes, such as sedimentation or filtration. Only when the particles are brought together into a floc can they settle out of the water column and be effectively removed, resulting in clearer and cleaner water.

While solubility, inertness, and non-toxicity are important properties for coagulants to consider, they do not directly address the primary functional requirement of coagulation, which is the production of an insoluble floc for effective particle removal.